1. Field of the Invention
This invention relates to a vial access adapter connectable to a vial which contains a medical fluid therein and is closed by an elastomeric stopper, wherein the vial access adapter is provided with a dual spike, one for withdrawing the medical fluid from the vial, and the other for simultaneous entry of air into the vial.
2. Reported Developments
Vials made of glass or polymeric materials, the walls of which are non-collapsible, require an air inlet when medical fluid is withdrawn therefrom to prevent the formation of vacuum therein. Typically, vials containing a medical fluid are closed by rubber stoppers which are pierced by a dual spike having a medical fluid passage and an air inlet passage, therein. The air inlet passage contains a filter to prevent entry of particulate matter or bacteria into the vials during the medicament withdrawal process.
The prior art has provided devices comprising a liquid flow passage and an air flow passage, such as disclosed, for example, in U.S. Pat. Nos. 3,359,977, 3,608,550, 3,783,895, 4,262,671, 4,505,709, 4,588,403, 4,787,898, 5,358,501, and 5,636,660. These inventions have advanced the prior art by providing convenient adapters and transfer devices connectable to containers of medical fluids.
In addition to providing in a vial access adapter a dual spike for withdrawing a medical fluid from a vial and simultaneously introducing filtered atmospheric air into the vial, the present invention also provides an elastomeric seal positioned in the fluid passage flow of the dual spike for hermetically sealing the fluid flow passage. In a preferred embodiment the elastomeric seal is of an M-shaped configuration through which the medical fluid can be accessed repeatedly. After each withdrawal of the desired amount of the medical fluid the elastomeric seal reseals itself thereby preventing contamination of the medical fluid by air-born particles, such as dust and bacteria.
A further improvement in the present invention over the prior art is the spatial configuration of the medical fluid access spike which, on positioning of the vial access adapter over a vial having a rubber stopper, penetrates the rubber stopper and just clears the bottom surface of the rubber stopper. This spatial configuration allows essentially complete withdrawal of the medical fluid contained in the vial.